Manual work is still very prevalent in many jobs today. This paper will explore the historic role that biomechanics has played in understanding these outcomes, as well as reviewing various prevention strategies used today.
The focus of the presentation will be on occupational low back pain. The discussion begins with the fundamental biomechanical reality; that the lumbar spine is often subjected to extremely large compression forces when one stoops to pick up an object, even if the object is of moderate weight. The paper will discuss this outcome, as well as biomechanics research in the late 80s that lead to inclusion in 1994 of a torso twisting risk factor in the “NIOSH Lifting Guideline.”
The growing use of mechanical aids (hoists, articulated arms and conveyors) has done a great deal to alleviate high levels of low back stress while lifting, but too often these same devices require people to twist and push and pull objects. High torso muscle antagonistic actions and vertebral shear forces were being predicted in such activities, especially when fast motions were involved. Concern also over shoulder injuries was growing related to the use of these devices, leading to the need to develop and use models of whole body exertions in industry to understand the full complexity of the problems for various groups of people.
Recently some biomechanics research began to focus on another aspect of vertebral column function that makes it vulnerable to injury, particularly during fast motions with light loads. This vulnerability is due to the column's reliance on well coordinated torso muscle contractions to control its inherent dynamic instability.
Get full access to this article
View all access options for this article.
References
1.
AdamsM. A.McNallyD. S.WagstaffJ.GoodshipA. E., “Abdominal Stress Concentrations in Lumbar Intervertebral Discs following Damage to the Vertebral Bodies: A Cause of Disc Failure,” European Spine Journal, 1, 214–221 (1993).
2.
AdamsM.FreemanB. J. C.MorrisonH. P.NelsonI. W.DolanP., “Mechanical Initiation of Intervertebral Disc Degeneration,” Spine, 25(13), 1625–1636 (2000).
3.
BeanJ. C.ChaffinD. B.SchultzA. B. “Biomechanical Model Calculation of Muscle Contraction Forces: A Double Linear Programming Method,” J. Biomech., 21(1), 59–66 (1988).
4.
BodénA.ObergK., “Torque Resistance of the Passive Tissues of the Trunk at Axial Rotation,” Applied Ergonomics, 29(2), 111–118 (1998).
5.
BrinckmannP.JohannlewelingN.HilwegD.BiggemanM., “Fatigue Fracture of Human Lumbar Vertebrae,” Clin. Biomech., 2, 94–96 (1987).
6.
ChaffinD. B.AnderssonG.B.J.MartinB. J., Occupational Biomechanics(3rd Edition) J. Wiley & Sons, New York, NY1999.
7.
ChaffinD. B., “Development of Computerized Human Static Strength Simulation Model for Job Design,” Human Factors and Ergonomics in Manufacturing, 7(4), 305–322 (1997).
8.
ChaffinD. B., “On the Validity of Biomechanical Models of the Low Back for Weight Lifting Analysis,” ASME Proceedings, 75-WA-Bio-1, Amer. Soc. Of Mech. Eng., New York, 1975.
9.
ChaffinD. B.RedfernM. S.ErigM.GoldsteinS. A., “Lumbar Muscle Size and Location Measurements from CT Scans of 96 Older Women,” Clin. Biomech., 5(1), 9–16 (1990).
10.
ChaffinD. B.SchutzR. K.SnyderR. G., A Prediction Model of Human Volitional Mobility, SAE Paper 720002, Soc. of Auto. Eng., Detroit, 1972.
11.
CholewickiJ.VanVlietJ. J.. “Relative Contribution of Trunk Muscles to the Stability of the Lumbar Spine during Isometric Exertions,” Clin. Biomech., 17, 99–105 (2002).
12.
CholewickiJ.AdamP. D.SimonsD.RadeboldA., “Effects of External Trunk Loads on Lumbar Spine Stability,” J. Biomech.33, 1377–1385 (2000).
13.
DeLoozeM. P.KingmasI.ThunnissenW.VanWijkM. J.ToussaintH. M., “The Evaluation of a Practical Biomechanical Model Estimating Lumbar Moments in Occupational Activities,” Ergonomics, 38(9), 1495–1502 (1994).
14.
El-BassoussiM. M., A Biomechanical Dynamic Model for Lifting in the Sagittal Plane, unpublished doctoral dissertation, Texas Technological University, Lubbock, TX, 1974.
15.
FarfanH. F.GracovetskyS. “The Nature of Instability,” Spine, 9(7), 714–719 (1984).
16.
FathallahF. A.MarrasW. S.ParnianpourM., The Role of Complex Simultaneous Trunk Motions in the Risk of Occupationally-related Low Back Disorders. Spine, 23(9):1035–1042 (1998).
17.
FisherB. O., Analysis of Spinal Stresses during Lifting, unpublished master's thesis, University of Michigan, Ann Arbor, MI, 1967.
18.
FoustD. R.ChaffinD. B.SnyderR. G.BaumJ. K., Cervical Range of Motion and Dynamic Response and Strength of Cervical Muscle. Reprinted November 1973 and 1974, SAE Transactions, 4(82), SAE Paper No. 730975, 1973.
19.
FreivaldsA.ChaffinD. B.GargA.LeeK. S., “A Dynamic Biome-chanical Evaluation of Lifting Maximum Acceptable Loads,” J. Biomech., 17(4), 251–262 (1984).
GenaidyA. M.WalyS. M.KhalilT. M.HidalgoJ., “Spinal Compression ToleranceLimits for the Design of Manual Material Handling Operations in the Workplace,” Ergonomics, 36(4), 415–434 (1993).
22.
GranataK. P.OrishimoK. F., “Response of Trunk Muscle Coactivation to Changes in Spinal Stability,” J. Biomech.34, 1117–1123 (2001).
23.
HughesR. E.ChaffinD. B., “Shear Force Considerations in Predicting Torso Muscle Antagonism,” Proceedings of the American Society of Biomechanics, Davis, CA, 1987.
24.
HughesR. E.ChaffinD. B., “The Effect of Strict Muscle Stress Limits on Abdominal Muscle Force Predictions for Combined Torsion and Extension Loadings,” J. Biomechanics, 28(5), 527–533 (1995).
25.
JägerM.LuttmannA.GöllnerR.LaurigW., “The Dortmunder-Biomechanical Model for Quantification and Assessment of the Load on the Lumbar Spine,” SAE Proceedings, 2001–01–2085, 2001.
26.
JägerM., Biomechanisches Modell des Menschen zu Analyse und Beurteilung der Belastung der Wirbelsaule bei der Handhabung von Lasten, VDI Verlage, Reihe 17 Boeechnik Nr. 33 (1987).
27.
KromodihardjoS.MitalA., “Kinetic Analysis of Manual Lifting Activities: Part I-Development of a Three-Dimensional Computer Model,” Int. J. Ind. Ergonomics, 1, 77–90 (1986).
28.
KumarS., “Moment Arms of Spinal Musculature Determined from CT Scans,” Clin. Biomech., 3, 137–144 (1988).
29.
LeeK. S., Biomechanical Modeling of Cart Pushing and Pulling, unpublished doctoral dissertation, University of Michigan, Ann Arbor, MI, 1982.
30.
MannionA. F.AdamsM. A.DolanP., “Sudden and Unexpected Loading Generates High Forces on the Lumbar Spine,” Spine, 25(7), 842–852 (2000).
31.
MarrasW. S.MirkaG. A., “Intra-abdominal Pressure during Trunk Extension Motions,” Clin. Biomech., 11(5), 267–274 (1996).
32.
MarrasW. S.GranataK. P., “A Biomechanical Assessment and Model of Axial Twisting in the Thoracolumbar Spine,” Spine, 20(13), 1440–1451 (1995).
33.
MarrasW. S., “Trunk Motion during Lifting: Temporal Relations among Loading Factors,” Int. J. Ind. Ergonomics, 1, 159–167 (1987).
34.
McGillS. M.NormanR. W., “Dynamically and Statically Determined Low Back Moments During Lifting,” J. Biomech., 18(12), 877–885 (1985).
35.
McGillS. M.NormanR. W., “Partitioning of the L4-L5 Dynamic Moment into Disc, Ligamentous, and Muscular Components during Lifting,” Spine, 11(7), 665–678 (1986).
36.
McGillS. M.NormanR. W., “Reassessment of the Role of Intra-abdominal Pressure in Spinal Compression,” Ergonomics, 30(11), 1565–1588 (1987).
37.
McGillS. M., “A Myoelectrically Based Dynamic Three-Dimensional Model to Predict Loads on Lumbar Spine Tissues during Lateral Bending,” J. Biomechanics, 25(4), 395–414 (1992).
38.
McGillS. M., “The Biomechanics of Low Back Injury: Implications on Current Practice in Industry and the Clinic, ISB Keynote Lecture,” J. Biomech., 30(5), 465–475 (1997).
39.
McGillS. M.PattN.NormanR. W., “Measurement of the Trunk Musculature of Active Males Using CT Scan Radiography Implications for Force and Moment Generating Capacity about the L4/L5 Joint,” J. Biomech., 21(4), 329–341 (1988).
40.
Medical Research Laboratory, Wright-Patterson AFB, Ohio, 1971. Kromodihardjo, S. and A. Mital, “Kinetic Analysis of Manual Lifting Activities: Part I-Development of a Three-Dimensional Computer Model,” Int. J. Ind. Ergonomics, 1, 77–90 (1986).
41.
MogaP. J.ErigM.ChaffinD. B.NussbaumM. A., “Torso Muscle Moment Arms at Intervertebral Levels T10 through L5 from CT Scans on Eleven Male and Eight Female Subjects,” Spine18(15), 2305–2309 (1993).
42.
MorrisJ. M.LucasD. B.BresslerB.. “Role of the Trunk in Stability of the Spine,” J. Bone Jt. Surg., 43A, 327–351 (1961).
43.
NachemsonA.ElfstromG., “Intravital Dynamic Pressure Measurements in Lumbar Disc,” Scand. J. Rehab. Med. (Supp. 1), 1–39 (1970).
44.
NemethG.OhlsenH., “Moment Arm Lengths of Trunk Muscles to the Lumbosacral Joint Obtained in Vivo with Computed Tomography,” Spine, 11(2), 158–160 (1986).
45.
NIOSH (National Institute for occupational Safety and Health), A Work Practices Guide for Manual Lifting, Tech. Report No. 81–122, U.S. Dept. of health and Human Services (NIOSH), Cincinnati, 1981.
46.
NussbaumM. A.ChaffinD. B.RechtienC. J., “Muscle Lines-of-Action Affect Predicted Forces in Optimization-Based Spine Muscle Modeling,” J. Biomechanics, 28(4), 401–409 (1995).
47.
ParkK. S.ChaffinD. B., “A Biomechanical Evaluation of Two Methods of Manual Load Lifting,” AIIE Trans., 6(2), 105–113 (1974).
48.
PopeM. H.AnderssonG. B. J.BromanH.SvenssonM.ZetterbergC., “Electromyographic Studies of the Lumbar Trunk Musculature during the Development of Axial Torques,” J. Orth. Res., 4, 288–297 (1986).
49.
SchultzA. B.AnderssonB. J. G., “Analysis of Loads on the Lumbar Spine,” Spine, 6(1), 76–82 (1981).
50.
SchultzA. B.HaderspeckK.WarwickD.PortilloD., “Use of Lumbar Trunk Muscles in Isometric Performance of Mechanically Complex Standing Tasks,” J. Orth. Res., 1, 77–91 (1983).
51.
ThelenD. G.SchultzA. B.Ashton-MillerJ. A., “Co-contraction of Lumbar Muscles during the Development of Time-Varying Triaxial Moments,” Journal of Orthopaedic Research, 13, 390–398 (1995).
52.
TveitP.DaggfeldtK.HetlandK. S.ThorstenssonA., “Erector Spinae Lever Arm Length Variations with Changes in Spinal Curvature,” Spine, 19(2), 199–204 (1994).
53.
Van DieënJ. H.ToussaintH. M.. “Evaluation of the Probability of Spinal Damage Caused by Sustained Cyclic Compression Loading,” Human Factors, 39(3), 469–480 (1997).
54.
WatersT. R.Putz-AndersonV.GargA.FineL. J.. “Revised NIOSH Equation for the Design and Evaluation of Manual Lifting Tasks,” Ergonomics, 36(7), 749–776 (1993).
55.
ZetterbergC.AnderssonG. B. J.SchultzA. B., “The Activity of Individual Trunk Muscles during Heavy Physical Loading,” Spine, 12(10), 1035–1040 (1987).
